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Children with hemato-oncological diseases may have significant skeletal morbidity, not only during and after treatment but also at the time of diagnosis before cancer treatment. This study was designed to evaluate the vitamin D status and circulating bone metabolic markers and their determinants in children at the time of diagnostic evaluation for hemato-oncological disease. This cross-sectional study included 165 children (91 males, median age 6.9 yr range 0.2–17.7 yr). Of them, 76 patients were diagnosed with extracranial or intracranial solid tumors, 83 with leukemia, and 6 with bone marrow failure. Bone metabolism was assessed by measuring serum 25OHD, PTH, bone alkaline phosphatase, intact N-terminal propeptide of type I procollagen, and C-terminal cross-linked telopeptide of type I collagen. Vitamin D deficiency was found in 30.9% of children. Lower 25OHD levels were associated with older age, lack of vitamin D supplementation, season outside summer, and a country of parental origin located between latitudes −45° and 45°. Children diagnosed with leukemia had lower levels of markers of bone formation and bone resorption than those who had solid tumors or bone marrow failure. In conclusion, vitamin D deficiency was observed in one-third of children with newly diagnosed cancer. Bone turnover markers were decreased in children with leukemia, possibly because of the suppression of osteoblasts and osteoclasts by leukemic cells. The identification of patients with suboptimal vitamin D status and compromised bone remodeling at cancer diagnosis may aid in the development of supportive treatment to reduce the adverse effects of cancer and its treatment. Lay Summary This study was designed to evaluate the vitamin D status and circulating bone metabolic markers in children with hemato-oncological diseases. Vitamin D deficiency was found in one-third of children. Lower vitamin D levels were associated with older age, lack of vitamin D supplementation, season outside summer, and a country of parental origin located between latitudes −45° and 45°. Children diagnosed with leukemia had lower levels of markers of bone formation and bone resorption than those who had solid tumors or bone marrow failure. The identification of patients with suboptimal vitamin D status and compromised bone remodeling may aid in the development of supportive treatment to reduce the adverse effects of cancer and its treatment. Graphical Abstract Graphical Abstract

Abstract Context Denosumab discontinuation is characterized by an increase in bone turnover overriding pretreatment status, a rapid bone loss in the majority and multiple vertebral fractures (VFx) in some patients. Methods A working group of the European Calcified Tissue Society performed an updated systematic review of existing literature on changes of bone turnover, bone mineral density (BMD), and fracture risk after denosumab discontinuation and provided advice on management based on expert opinion. Results Important risk factors for multiple VFx following denosumab cessation are prevalent VFx, longer duration off therapy, greater gain in hip BMD during therapy, and greater loss of hip BMD after therapy according to a retrospective analysis of the FREEDOM Extension Study. Case series indicate that prior bisphosphonate therapy mitigates the biochemical rebound phenomenon after denosumab discontinuation, but it is uncertain whether this attenuation prevents BMD loss and fractures. Current evidence indicates partial efficacy of subsequent antiresorptive treatment with results seemingly dependent on duration of denosumab treatment. Conclusions A careful assessment of indications to start denosumab treatment is advised, especially for younger patients. A case for long-term treatment with denosumab can be made for patients at high fracture risk already on denosumab treatment given the favorable efficacy and safety profile. In case of denosumab discontinuation, alternative antiresorptive treatment should be initiated 6 months after the final denosumab injection. Assessment of bone turnover markers may help define the optimal regimen, pending results of ongoing randomized controlled trials. Patients who have sustained VFx should be offered prompt treatment to reduce high bone turnover.

Bariatric surgeries such as Roux-en-Y gastric bypass (RYGB) and adjustable gastric banding (AGB) lead to long-term deficits in bone density but are also accompanied by decreased weight, which may lower the impact force with falls. The aim of this study was to compare the long-term skeletal impact of RYGB and AGB using a biomechanical evaluation of load-to-strength ratio at the distal radius as a surrogate for wrist fracture risk. We conducted a cross-sectional study evaluating bone microarchitectural parameters and bone turnover in adults who received either RYGB or AGB surgery ≥10 yr ago (RYGB: n = 22; AGB: n = 23). Bone strength at the distal radius was estimated by microfinite element analysis from HR-pQCT. We used a single-spring biomechanical model to estimate impact force and then calculated load-to-strength ratio as a ratio of impact force to bone strength, with higher load-to-strength ratios representing a higher susceptibility to fracture. In multivariable analyses, the RYGB group had higher bone resorption marker C-telopeptide (CTX) levels, lower volumetric bone density, and worse cortical and trabecular microarchitectural parameters than the AGB group. Furthermore, estimated bone strength at the radius was lower in the RYGB group (3725 ± 139 N vs 4141 ± 157 N, p = .030), and the load-to-strength ratio was higher in RYGB group as compared with AGB (0.84 ± 0.04 vs 0.72 ± 0.05, p = .035), suggestive of higher propensity for wrist fracture. Taken together, these results indicate the long-term deleterious skeletal effects are more concerning with RYGB than AGB. Lay Summary Though weight-loss surgery is an effective treatment for obesity, it can also result in bone loss. Additionally, previous research has found that certain types of weight-loss surgeries are associated with greater declines in BMD. Our study aimed to understand the differences in long-term bone health after RYGB vs AGB. In 22 individuals who had RYGB and 23 individuals who had AGB >10 yr ago, we examined bone strength at the wrist and evaluated a novel estimate of fracture risk called the “load-to-strength” ratio. We found that the RYGB group had a higher average load-to-strength ratio, indicating a higher propensity for wrist fracture, as compared to the AGB group. Thus, we demonstrated that, compared to individuals who receive AGB, individuals who receive RYGB have lower bone strength at the wrist and may be more susceptible to wrist fractures in the long term. Graphical Abstract Graphical Abstract

Abstract Context Zoledronate is used to prevent bone loss following denosumab discontinuation but its efficacy differs among studies. Objective To test if the duration of denosumab treatment affects the efficacy of subsequent zoledronate infusion. Methods This multicenter, prospective cohort study, conducted at 2 Greek and 1 Dutch bone centers, included 47 postmenopausal women (n = 47) who received a single zoledronate infusion 6 months after the last denosumab injection and then were followed for 1 year. Twenty-seven women received ≤ 6 denosumab injections (≤ 6 Group) and 20 received > 6 denosumab injections (> 6 Group). The main outcome measure was changes in lumbar spine (LS) bone mineral density (BMD). Results At 12 months LS-BMD values were maintained in the ≤ 6 Group (0.98 ± 0.10 to 0.99 ± 0.9 g/cm2, P = 0.409) but decreased significantly in the > 6 Group (1.0 ± 0.11 to 0.93 ± 0.12 g/cm2, P < 0.001). The percent change of LS-BMD of the ≤ 6 Group (+1.0%) was significantly different (P < 0.001) from the change of the > 6 Group (−7.0%). In the whole cohort, the duration of denosumab treatment was negatively correlated with the percentage change of LS-BMD (rs = −0.669, P < 0.001) but not with the change of femoral neck (FN)-BMD. Bone turnover markers increased in all patients 6 months following zoledronate administration with no difference between the 2 groups. Conclusion The duration of denosumab treatment significantly affects the efficacy of subsequent zoledronate infusion to maintain BMD gains. Frequent follow-up of patients treated with denosumab longer than 3 years is advisable as additional therapeutic interventions may be needed.

Abstract Context The risk of fragility fractures is increased in both type 1 and type 2 diabetes. Numerous biochemical markers reflecting bone and/or glucose metabolism have been evaluated in this context. Objective This review summarizes current data on biochemical markers in relation to bone fragility and fracture risk in diabetes. Methods A group of experts from the International Osteoporosis Foundation and European Calcified Tissue Society reviewed the literature focusing on biochemical markers, diabetes, diabetes treatments, and bone in adults. Results Although bone resorption and bone formation markers are low and poorly predictive of fracture risk in diabetes, osteoporosis drugs seem to change bone turnover markers (BTMs) in diabetics similarly to nondiabetics, with similar reductions in fracture risk. Several other biochemical markers related to bone and glucose metabolism have been correlated with bone mineral density and/or fracture risk in diabetes, including osteocyte-related markers such as sclerostin, glycated hemoglobin A1c (HbA1c) and advanced glycation end products, inflammatory markers, and adipokines, as well as insulin-like growth factor-1 and calciotropic hormones. Conclusion Several biochemical markers and hormonal levels related to bone and/or glucose metabolism have been associated with skeletal parameters in diabetes. Currently, only HbA1c levels seem to provide a reliable estimate of fracture risk, while BTMs could be used to monitor the effects of antiosteoporosis therapy.

SummaryThe National Bone Health Alliance (NBHA) recommends standardized sample handling and patient preparation for C-terminal telopeptide of type I collagen (CTX-I) and N-terminal propeptide of type I procollagen (PINP) measurements to reduce pre-analytical variability. Controllable and uncontrollable patient-related factors are reviewed to facilitate interpretation and minimize pre-analytical variability.IntroductionThe IOF and the International Federation of Clinical Chemistry (IFCC) Bone Marker Standards Working Group have identified PINP and CTX-I in blood to be the reference markers of bone turnover for the fracture risk prediction and monitoring of osteoporosis treatment. Although used in clinical research for many years, bone turnover markers (BTM) have not been widely adopted in clinical practice primarily due to their poor within-subject and between-lab reproducibility. The NBHA Bone Turnover Marker Project team aim to reduce pre-analytical variability of CTX-I and PINP measurements through standardized sample handling and patient preparation.MethodsRecommendations for sample handling and patient preparations were made based on review of available publications and pragmatic considerations to reduce pre-analytical variability. Controllable and un-controllable patient-related factors were reviewed to facilitate interpretation and sample collection.ResultsSamples for CTX-I must be collected consistently in the morning hours in the fasted state. EDTA plasma is preferred for CTX-I for its greater sample stability. Sample collection conditions for PINP are less critical as PINP has minimal circadian variability and is not affected by food intake. Sample stability limits should be observed. The uncontrollable aspects (age, sex, pregnancy, immobility, recent fracture, co-morbidities, anti-osteoporotic drugs, other medications) should be considered in BTM interpretation.ConclusionAdopting standardized sample handling and patient preparation procedures will significantly reduce controllable pre-analytical variability. The successful adoption of such recommendations necessitates the close collaboration of various stakeholders at the global stage, including the laboratories, the medical community, the reagent manufacturers and the regulatory agencies.

Summary Thyrotoxicosis leads to loss of bone mass. Vitamin D is important to bone health. In this randomized, placebo-controlled trial, we showed that bone restoration did not improve when adding vitamin D supplementation to standard care of Graves’ disease thyrotoxicosis. Bone density and microarchitecture improved markedly with treatment of thyrotoxicosis. Purpose Vitamin D is important to skeletal health and ensuring a replete vitamin D status is recommended. In thyrotoxicosis, bone turnover is increased and bone mass density (BMD) reduced. We examined whether vitamin D supplementation improves bone recovery in thyrotoxicosis caused by Graves’ disease (GD). Methods Using a double-blinded design, hyperthyroid patients with GD were randomized to vitamin D3 70 µg/day (2800 IU) or similar placebo as add-on to antithyroid drugs (ATD). At baseline and 9 months, we measured BMD and bone architecture using DXA and high resolution peripheral quantitative computerized tomography. Bone turnover markers (BTM) were measured at 3 months also. Effect of vitamin D versus placebo and the response to ATD treatment were analyzed using linear mixed modelling. Results Eighty-six GD patients were included (age 41 ± 14 years, 86% females). Compared to placebo, vitamin D3 did not improve BMD or microarchitecture. In response to ATD, BMD increased in the hip by 2% (95%CI: 1–4%). Cortical porosity decreased in tibia (− 7% [95%CI: − 12 to − 2%]) and radius [− 14% [95%CI: − 24 to − 3%]), and trabecular thickness increased (tibia (5% [95%CI: 2 − 9%]) and radius (4% [95%CI: 1–7%]). Changes in BTM, but not thyroid hormones, were associated with changes in BMD by DXA and with changes in the cortical compartment. Conclusion In newly diagnosed GD, 9 months of high dose vitamin D3 supplementation does not offer benefit by improving skeletal health. Treatment of thyrotoxicosis is associated with the recovery of BMD and microarchitecture. Clinicaltrial.gov identifier NCT02384668

Bone turnover markers (BTMs) are released during the bone remodelling cycle and are measurable in blood or urine, reflecting bone remodelling rate. They have been useful in elucidating the pharmacodynamics and effectiveness of osteoporosis medication in clinical trials and are increasingly used in routine clinical management of osteoporosis, especially for monitoring therapy, in addition to their use in other metabolic bone disease such as Paget’s disease of bone and osteomalacia. Serum β isomerised C-terminal telopeptide of type I collagen and pro-collagen I N-terminal propeptide have been designated as reference BTMs for use in osteoporosis. In addition, bone-specific isoenzyme of alkaline phosphatase (B-ALP) secreted by osteoblasts and tartrate-resistant acid phosphatase 5b (TRACP-5b) secreted by osteoclasts are also found to be specific markers of bone formation and resorption, respectively. The concentrations of the latter enzymes in blood measured by immunoassay provide reliable measures of bone turnover even in the presence of renal failure. B-ALP is recommended for use in the assessment of renal bone disease of chronic kidney disease, and TRACP-5b shows promise as a marker of bone resorption in that condition. BTMs in blood do not suffer from biological variation to the same extent as the older BTMs that were measured in urine. Appropriate patient preparation and sample handling are important in obtaining accurate measures of BTMs for clinical use. Reference change values and treatment targets have been determined for the reference BTMs for their use in monitoring osteoporosis treatment. Further ongoing studies will enhance their clinical applications.

A healthy skeleton depends on a continuous renewal and maintenance of the bone tissue. The process of bone remodeling is highly controlled and consists of a fine-tuned balance between bone formation and bone resorption. Biochemical markers of bone turnover are already in use for monitoring diseases and treatment involving the skeletal system, but novel biomarkers reflecting specific biological processes in bone and interacting tissues may prove useful for diagnostic, prognostic, and monitoring purposes. The Wnt-signaling pathway is one of the most important pathways controlling bone metabolism and consequently the action of inhibitors of the pathway such as sclerostin and Dickkopf-related protein 1 (DKK1) have crucial roles in controlling bone formation and resorption. Thus, they might be potential markers for clinical use as they reflect a number of physiological and pathophysiological events in bone and in the cross-talk with other tissues in the human body. This review focuses on the clinical utility of measurements of circulating sclerostin and DKK1 levels based on preanalytical and analytical considerations and on evidence obtained from published clinical studies. While accumulating evidence points to clear associations with a number of disease states for the two markers, and thus, the potential for especially sclerostin as a biochemical marker that may be used clinically, the lack of standardization or harmonization of the assays still hampers the clinical utility of the markers.

Purpose This study aimed to evaluate the effects of thyroid-stimulating hormone (TSH) suppressive therapy on bone mineral density (BMD) and bone turnover markers (BTMs) in differentiated thyroid cancer (DTC) patients after postoperative 1–2 years in Northeast China. Methods Five male, sixteen premenopausal, and eight postmenopausal female DTC patients receiving TSH suppressive therapy after thyroidectomy were enrolled. Patients were matched with healthy controls in a ratio of 1:2. All participants completed postoperative 1-year follow-up, and postmenopausal women completed 2-year follow-up. We measured BMD of the lumbar spine (LS), femoral neck (FN), and total hip (TH) using dual-energy X-ray absorptiometry (DXA). Bone formation marker P1NP and bone resorption marker β -CTX were also evaluated. Fracture risks were assessed by FRAX. Results There was no difference in BMD and BTMs between DTC patients and controls in the male group at 1-year follow-up. In the premenopausal women, the baseline P1NP was significantly lower in DTC patients than in the controls. The LS-BMD, FN-BMD, and TH-BMD in DTC patients were all higher than those in controls at 1-year follow-up. The difference in FN-BMD was not significant after adjusting for baseline P1NP. In the postmenopausal women, no differences in BMD and BTMs were observed between DTC patients and controls at the 1-year and 2-year follow-up. Conclusion Our study indicated that postoperative 1-year TSH suppressive therapy did not show detrimental effects on BMD and BTMs in men, premenopausal, and postmenopausal DTC patients. The 2-year postoperative TSH suppressive therapy did not lead to additional loss of bone mass in postmenopausal DTC patients.